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Author Topic: Anyone have a "speed chart" they can copy?  (Read 1502 times)

Offline Skip Chernoff

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Anyone have a "speed chart" they can copy?
« on: April 10, 2018, 07:31:16 PM »
I'm looking for some type of chart that that will convert my "timed runs" on 60' lines to speed in MPH ? Someone has to have something like that ,right? Thanks,Skip

Offline Bob Heywood

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Re: Anyone have a "speed chart" they can copy?
« Reply #1 on: April 10, 2018, 08:03:52 PM »
The attached 1/2 Mile Speed Chart is calculated using the regulation formula found in the C/L Speed Rules. For 60 ft lines the timed run is 7 laps. Watch times are in seconds to the nearest 0.01 sec. Bear in mind that the calculation is based on a 60 ft flying radius. If you walk a center circle and extend your arm your actual radius will be greater than 60 ft. Practice standing right in the center of the pad and hold your handle as close to your chest as possible for your best times.

Fly low...Fly fast...

The scans are near the attachment limit for posts so I had to do the sheets one at a time.
"Clockwise Forever..."

Offline Bob Heywood

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Re: Anyone have a "speed chart" they can copy?
« Reply #2 on: April 10, 2018, 08:04:36 PM »
Pg 2
"Clockwise Forever..."

Offline Bob Heywood

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Re: Anyone have a "speed chart" they can copy?
« Reply #3 on: April 10, 2018, 08:05:09 PM »
Pg 3
"Clockwise Forever..."

Offline Bob Heywood

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Re: Anyone have a "speed chart" they can copy?
« Reply #4 on: April 10, 2018, 08:05:51 PM »
Pg 4
"Clockwise Forever..."

Offline Skip Chernoff

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Re: Anyone have a "speed chart" they can copy?
« Reply #5 on: April 11, 2018, 05:53:21 AM »
Thanks Much ,Chart #4 was the one I was looking for. Cheers,Skip

Offline Paul Smith

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Re: Anyone have a "speed chart" they can copy?
« Reply #6 on: April 11, 2018, 08:06:48 AM »
The formula is simple enough:

For a half mile, 1800/seconds.

For a mile or kilometer, 3600/seconds.

Thus for a Perky Speed, 36 seconds = 100 MPH.

For an F2A, 12 seconds = 300 KPH.
« Last Edit: April 11, 2018, 10:42:18 AM by Paul Smith »
Paul Smith

Offline Bob Heywood

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Re: Anyone have a "speed chart" they can copy?
« Reply #7 on: April 11, 2018, 08:33:21 AM »
The formula is simple enough:

For a half mile, seconds/1800.

For a mile or kilometer, seconds/3600.

Thus for a Perky Speed, 36 seconds = 100 MPH.

For an F2A, 12 seconds = 300 KPH.

This simplistic approach only works for FAI. It DOES NOT work for AMA because the regulation distance is not a true half-mile. For 60 ft lines the 7 lap regulation distance is 2638.94 ft. or 0.4998 mile. While the difference is small it is not negligible. In Speed Record Racing timing must be as precise as possible. Using the correct factors is the only way that speeds from different venues at different times can be compared to one and another.

The correct 7 lap factor is 1799.28 and the 14 lap factor is 3598.56. For 52 ft 6 in lines these factors also work for 8 laps and 16 laps respectively.

The only reason FAI works out is because the specified line length is set so an even number of laps equals 1 km. The lines end up being an odd length, measured to fractions of a meter.

BTW Paul, your ratios are inverted.
"Clockwise Forever..."

Offline Paul Smith

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Re: Anyone have a "speed chart" they can copy?
« Reply #8 on: April 11, 2018, 10:52:46 AM »
Yes, Bob is quite correct.

The simple formula actually defines a mile as only 5,277.88 feet.  For my formula to be true, your lines would been to be 60' - .02414997" in length.

So a Fox Speed model that clocks 36.00 seconds would be scored at 100 MPH my way or 99.96 MPH Bob's way.

Considering the measurement with a tape measure, the lack of a pylon, and timing with a hand-operated stop watch, the 3600 is more than accurate enough.

There are accepted scientific principles against the production of results to finer resolution than the input data.
Paul Smith

Offline Skip Chernoff

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Re: Anyone have a "speed chart" they can copy?
« Reply #9 on: April 11, 2018, 02:10:25 PM »
Thanks both of you for jumping in. Today I went out to do some testing on my Sportsman Speed entry and I blew out the "base" gasket between the jug and case. Would it be ok for me to make a new one out of soft aluminum,instead of paper?

Offline john e. holliday

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Re: Anyone have a "speed chart" they can copy?
« Reply #10 on: April 11, 2018, 03:15:40 PM »
Why should it not be exceptable to replace a paper gasket with aluminum if it is the same thickness! HB~>
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Offline Jim Carter

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Re: Anyone have a "speed chart" they can copy?
« Reply #11 on: April 11, 2018, 04:59:35 PM »
 ;D  Howdy Skip!  Personally, I have the NCLRA Speed Chart, bookmarked on my iPhone so whenever me and the guys I fly with want a basic idea of how fast a plane is, we plug in the line length and plug in the flight time we get for "x" number of laps (usually we go for 3 or 4 individual one lap times and other times we may count more laps but generally we just take the time for one lap about 3 - 4 times throughout a flight, average them, then plug that time into the speed calculator).  We're not looking for any kind of record setting just a general idea of how well a particular plane is performing.  Maybe it will work for you:  http://www.nclra.org/Programs/Speeds.php

Offline Paul Smith

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Re: Anyone have a "speed chart" they can copy?
« Reply #12 on: April 12, 2018, 06:48:52 AM »
Why should it not be exceptable to replace a paper gasket with aluminum if it is the same thickness! HB~>

In the Sport Speed event at The Brodak we will follow the custom of allowing replacement of bolts, gaskets and such things in the stock engine class. 
This does not extend to gutting engine and replacing the innards with the works of a Nelson or an OPS, as is permitted in Fox 35 Stunt Speed.
Paul Smith


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